The Genitalia of the Apsilocephalidae (Diptera)

The male and female genitalia of Apsilocephala longistyla and Clesthentia sp., and the female genitalia of Clesthentiella crassioccipitis, are described and illustrated. The male genitalia of the Apsilocephalidae are unique and can be easily distinguished from those of other related families (Therevidae, Asilidae, Bombyliidae, Empididae and Dolichopodidae). There are three spermathecae in the Apsilocephalidae, but only one in the Empididae and Dolichopodidae.